Delete contents of C:\Users\[YourName]\AppData\Local\3uTools (back up first).
Error Code 13 frequently appears on new Windows 10/11 builds because is turned on by default in the latest updates. This feature blocks 3uTools from accessing your documents or cache. 3utools failed to access folder error code 13 new
User may have set a custom working folder without proper permissions. 3utools failed to access folder error code 13 new
Back up your registry first.